Cationic antimicrobial peptides (CAMPs), important for regulating the innate immune system of plants, insects, and animals (Zasloff M (2002) Antimicrobial peptides of multicellular organisms. Nature 415:389-395.), are recognized as candidates against bacterium and fungi originally (Rothstein D M, Spacciapoli P, Tran L T, Xu T, Roberts F D, et al. (2001) Anticandida activity is retained in P-113, a 12-amino-acid fragment of histatin 5. Antimicrob. Agents Chemother. 45: 1367-1373; Yu H Y, Huang K C, Yip B S, Tu C H, Chen H L, et al. (2010) Rational design of tryptophan-rich antimicrobial peptides with enhanced antimicrobial activities and specificities. Chembiochem 11: 2273-2282.). CAMPs are normally characterized by their positive charges and amphipathic features, which enable them to bind to negatively charged bacterial cell membranes and cause a disruption of the membrane, hence the death of bacterium (Hancock R E and Sahl H G (2006) Antimicrobial and host-defense peptides as new anti-infective therapeutic strategies. Nat Biotechnol 24: 1551-1557.; La Rocca P, Shai Y and Sansom M S (1999) Peptide-bilayer interactions:simulations of dermaseptin B, an antimicrobial peptide. Biophys Chem 76:145-159.). The membrane lytic property of CAMPs makes them potential therapeutics for overcoming the antibiotic resistance (Yu H Y, Huang K C, Yip B S, Tu C H, Chen H L, et al. (2010) Rational design of tryptophan-rich antimicrobial peptides with enhanced antimicrobial activities and specificities. Chembiochem 11: 2273-2282.).
Although tremendous efforts have been put into the development of new treatments, cancer remains the major cause of death (Siegel R, Ma J, Zou Z and Jemal A (2014) Cancer statistics 2014. CA Cancer J Clin 64: 9-29). Chemotherapies, despite their severe side effects to normal cells and tissues, and the easy formation of multi-drug resistances, are still the principal drugs used to treat cancer in the advanced or metastatic stages (Siegel R, Ma J, Zou Z and Jemal A (2014) Cancer statistics 2014. CA Cancer J Clin 64: 9-29).
Thus, the development of new cancer drugs with low toxicity to normal cells and a new mode of mechanism that can avoid multi-drug resistance may provide a new direction for anticancer therapy.
Accordingly, at present, a new peptide drug which has hypotoxicity to normal cells and has antimicrobial and anticancer activities is needed.